Departament de Biologia Cellular i Fisiologia, Facultat de Medicina, Universitat Autònoma de Barcelona, Spain.
Using fluorescence in situ hybridization techniques with either human or hamster genomic DNA probes, we studied the origin of micronuclei in two-cell hybrid embryos obtained from hamster oocytes and gamma-irradiated human spermatozoa. Our study demonstrates that over 99% of micronuclei hybridize with human DNA probes and not with hamster DNA, revealing their human origin. Thus, the micronucleus test represents a good method to evaluate genetic damage in human germ cells, since it is simpler and faster than sperm chromosome studies.